Comorbid Orbital Pseudolymphoma and Graves’ Ophthalmopathy Treated with Bilateral Combined Transcranial/Endoscopic Decompression and Rituximab

Introduction: Inflammatory orbitopathies are a heterogeneous group of autoimmune disorders that share a common presentation of exophthalmos attributable to intraorbital soft-tissue inflammatory infiltration and/or deposition. Graves’ ophthalmopathy is the quintessential example, in which a T lymphocyte-mediated reaction to antithyrotropin receptor antibodies generates dramatic mucopolysaccharide deposition within the extraocular muscles; however, several less common disorders present similarly, including orbital lymphoma, sarcoidosis, amyloidosis, and Erdheim Chester disease. We report a unique patient who presented with co-morbid biopsy-proven pseudolymphoma and Graves’ ophthalmopathy, which was treated with bilateral orbital decompression followed by rituximab.

Methods: Case report.

Results: A 61-year-old man presented with a 3-year history of progressive eye swelling, right greater than left. Graves’ disease was diagnosed via serum antibody testing, and an initial endoscopic orbital decompression at another facility was successful; however, the patient recurred after 5 weeks, and underwent total thyroidectomy and prednisone induction without significant improvement. He was subsequently referred to our clinic for additional therapies. On our assessment, he reported severe bilateral photophobia and mild but progressive visual loss. Physical exam was significant for left-greater-than-right proptosis, conjunctival injection, left optic neuropathy with disc swelling and venous congestion, and exposure keratitis with corneal thinning and scarring; extraocular movements were limited in all quadrants, and acuity testing was 20/30 on the right and 20/40 on the left. The patient was taken for bilateral fronto-orbital craniotomies with circumferential orbital decompression and periorbital release. The procedure was well tolerated, with significant bilateral proptosis reduction and early postoperative improvement in subjective visual acuity. Histopathologic analysis of a left lateral rectus biopsy demonstrated marked infiltration of polyclonal CD20+ lymphocytes without atypia, kappa/lambda expansion, or positive neoplastic markers. IgG4:IgG ratio was < 10%, negative for IgG4-related disorder, resulting in the diagnosis of benign pseudolymphoma. Ocular coherence tomography and visual fields at 3 months showed mild improvement only, and the patient demonstrated mild persistent left proptosis and left optic nerve atrophy; correspondingly, he was taken for an endoscopic right orbital decompression to maximize circumferential decompression and initiated on rituximab for intraorbital cytoreduction.

Conclusion: Inflammatory orbitopathies are uncommon disorders, and dual diagnoses are very rare. Patients with positive laboratory tests for Graves’ disease, IgG4-related disorder, or more prevalent causes of immune-mediated proptosis who do not respond to medical therapy should be considered for biopsy at the time of surgical decompression, particularly considering the propensity for auto-immune disorders to cluster in patients. Aggressive, combined surgical decompression is an excellent strategy for proptosis reduction and relief of intraorbital mass effect; however, refractory cases may also benefit substantially from adjuvant biologic therapy.